The role of surfactants in the reversal of active transport mediated by multidrug resistance proteins

A variety of seven nonionic, one amphoteric and, one anionic surfactant that are applied or investigated as surfactants in drug formulation, were analyzed for their capacity to modulate carrier-mediated transport by efflux pumps. Two cell lines, murine monocytic leukemia cells overexpressing P-glycoprotein (P-gp) and Madin-Darby canine kidney cells stably overexpresssing human multidrug resistance-associated protein 2 (MRP2), were used as test systems. The modulation of P-gp and of MRP2 function was studied by the reversal of rhodamine 123 and of methylfluorescein-glutathione conjugate transport, respectively. Mechanisms that were not transporter related and could lead to misinterpretations were identified, such as probe quenching, probe encapsulation by micelles, and membrane damage. P-gp-mediated rhodamine 123 transport was inhibited by five nonionic surfactants in a concentration-dependent manner and in the order TPGS > Pluronic PE8100 > Cremophor EL > Pluronic PE6100 approximately Tween 80. In contrast, none of the surfactants showed a significant inhibition of MRP2-mediated efflux in Madin-Darby canine kidney/MRP2 cells. In conclusion, the results indicate that surfactants demonstrate a transporter-specific interaction, rather than unspecific membrane permeabilization. The present analysis offers insight in the possible mechanisms of surfactant interactions with biological membranes and could help to identify specific drug formulations.     

Three-dimensional upper limb movement characteristics in children with hemiplegic cerebral palsy and typically developing children

The aim of this study was to measure which three-dimensional spatiotemporal and kinematic parameters differentiate upper limb movement characteristics in children with hemiplegic cerebral palsy (HCP) from those in typically developing children (TDC), during various clinically relevant tasks.We used a standardized protocol containing three reach tasks (forwards, upwards, and sideways), two reach-to-grasp tasks (with objects requiring different hand orientations), and three gross motor tasks. Spatiotemporal (movement duration, trajectory straightness, maximum velocity, and timing of maximum velocity), as well as kinematic parameters (discrete angles and waveforms of the trunk, scapula, shoulder, elbow and wrist), were compared between 20 children with HCP (age 10.9 ± 2.9 years) and 20 individually age-matched TDC (age 10.9 ± 3.0 years). Kinematic calculations followed the recommendations from the International Society of Biomechanics.Results showed that children with HCP had longer movement durations, less straight hand trajectories, and lower maximum velocities compared to the TDC. Timing of maximum velocity did not differ between both groups. The movement pathology in children with HCP was highlighted by increased trunk movements and reduced shoulder elevation during reaching and reach-to-grasp. We also measured an increased anterior tilting and protraction of the scapula in children with HCP, although differences were not significant for all tasks. Finally, compared to the TDC, children with HCP used less elbow extension and supination and more wrist flexion to execute all tasks.This study reported distinct 3D upper limb movement characteristics in children with HCP and age-matched TDC, establishing the discriminative ability of the measurement procedure. From a clinical perspective, combining spatiotemporal and kinematic parameters may facilitate the identification of the pathological movement patterns seen in children with HCP and thereby add to a well-targeted upper limb treatment planning.     

The Arm Profile Score: A new summary index to assess upper limb movement pathology

Although three-dimensional movement analysis is being increasingly used to evaluate upper limb (UL) movements, information on how to interpret the complex data is still missing. This paper introduces a new summary index, the “Arm Profile Score” (APS), to evaluate the severity of UL movement pathology based on kinematic data, similar to the “Gait Profile Score”. The APS is calculated from the root mean square (RMS) difference between kinematic data of the individual child with UL movement deficits and average data from typically developing children. The APS can be decomposed into 13 Arm Variable Scores (AVS), representing the different joint angles. The APS, together with the AVSs form the “Arm Movement Analysis Profile” (A-MAP).Face and construct validity were established for eight UL tasks in a group of 20 children with hemiplegic cerebral palsy (HCP). Intra-session variability was low for the different tasks, with median inter-quartile ranges below 2°. Correlation analysis showed few significant correlations between the individual AVSs and between the AVS and APS, implying that the A-MAP provides considerably more information compared to the APS only. The APS also showed good correlations with the House classification, and with measures of muscle tone, manual muscle strength and grip strength.This study provides a sound base to use the APS to evaluate UL movement pathology in children with HCP. Further study will need to confirm its value as an outcome measurement.     

Betaine homocysteine methyl transferase 1, a novel auto-antigen associated with anti-Golgi immune reactivity

Anti-Golgi antibodies are rare autoantibodies that have been described in systemic autoimmune diseases. Not all Golgi auto-antigens are known. The objective of this study was to identify a novel auto-antigen associated with anti-Golgi immune reactivity. Sera from a patient with Golgi immune reactivity and from a control individual were used for Western blotting after 2-dimensional gel separation of a rat Golgi-enriched extract. Betaine homocysteine S-methyltransferase 1 (BHMT1) was identified as an auto-antigen by MALDI-TOF/TOF mass spectrometry. Using human recombinant BHMT1, a strong positive blotting signal was obtained with serum from the patient but not from a control. Pre-absorption of the serum sample with reactivity to BHMT1 with recombinant human BHMT1 resulted in decreased reactivity on Western blotting and in disappearance of the Golgi-like pattern on indirect immunofluorescence. Using immunocytochemistry, we confirmed the subcellular localization of BHMT1 to the Golgi apparatus. Antibodies to BHMT1 were found in four of 80 samples with a Golgi-pattern on indirect immunofluorescence. The antibodies were not associated with a specific clinical condition. We identified BHMT1 as a novel auto-antigen associated with anti-Golgi immune reactivity.     

Weight, gender, and snack appeal

In this study, we hypothesized that overweight/obese persons have an exaggerated approach tendency toward high calorie foods. Testing this hypothesis, a stimulus response compatibility (SRC) task was used to assess approach-avoidance tendencies toward food in both overweight/obese participants (n=42), and normal weight controls (n=46). The SRC task is a reaction time task measuring how fast one approaches and avoids pictures of food and non-foods according to given instructions. It was found that overweight/obese men are slower at avoiding particularly high calorie snack foods. But this does not appear to be the case for overweight/obese women who showed nearly as fast avoidance as approach toward the high calorie food cues. It is concluded that overweight/obese women, rather than men, are ambivalent toward high calorie foods, which is the likely result of high dietary restraint.     

Genotyping and antimicrobial resistance patterns of Escherichia coli O157 originating from cattle farms

During a Escherichia coli O157 prevalence study on cattle farms, 324 E. coli O157 isolates were collected from 68 out of 180 cattle farms. All isolates harbored the eaeA gene and the enterohemolysin (ehxA) gene. The majority of the strains only contained vtx2 (245 isolates), the combination of vtx1 and vtx2 was detected in 50 isolates, and in 29 isolates none of the vtx genes was present. Pulsed-field gel electrophoresis (PFGE) revealed that at a similarity level of 98% the isolates grouped into 83 different genotypes, 76 of which were only detected on one farm. Twenty-two out of the 68 positive farms harbored isolates belonging to more than one PFGE type, with a maximum of four different PFGE types. Minimal inhibitory concentrations of 10 antimicrobial agents were determined on a subset of 116 isolates, that is, one isolate per positive age category per farm. Acquired resistance to at least one antimicrobial agent was detected in 18 isolates and within a farm, only one resistance pattern was observed. All these 18 isolates were resistant toward streptomycin, and 16 of them also showed resistance toward sulfisoxazole. Six isolates were resistant to three or more antimicrobial agents.     

Normative data and percentile curves for the three-minute walk test and timed function tests in healthy Caucasian boys from 2.5 up to 6 years old

The three-minute walk test (3MWT) and timed function tests (TFTs) (rise from floor, 10 m run, climbing and descending four stairs) are currently used to evaluate functional capacity in young boys with neuromuscular disorders. This study aimed to generate normative data in healthy boys aged 2.5 up to 6 years for these tests and to provide percentile curves according to age and height. The relation between the 3MWT, TFTs and anthropometric variables was investigated. In total 179 boys (mean age: 4.1 y ± 1.0) were evaluated across four age (2.5 years; 3 years; 4 years and 5 years) and three height groups: (<100 cm; 100 to <110 cm and ≥110 cm). Three-minute walk distance (3MWD) increased significantly, from 168.4 m (± 18.8) at 2.5 years to 214.5 m (± 26.1) at 5 years and from 172.6 m (±21.8) for children <100 cm to 212.7 m (±26.2) for children ≥110 cm. TFTs times decreased significantly with age and height. Significant correlations between the anthropometric values, 3MWD and TFTs were found (r(s)= 0.55–0.84; p <0.0001). These normative data and percentile curves provide a useful tool in the assessment of functional capacity in young boys. This study also confirms the association between functional tests and anthropometric values.     

Maturity offset in gymnasts: application of a prediction equation

PURPOSE: To verify the applicability of the prediction equation for maturity offset in a sample of female gymnasts followed longitudinally through adolescence. METHODS: Fifteen gymnasts were followed longitudinally for 6-7 yr across adolescence. Weight, height, and sitting height were measured at annual intervals. The Preece-Baines Model I was fitted to longitudinal height data for individual gymnasts to derive age at peak height velocity (PHV). The curve-fitting protocol was successfully fit to the height records of 13 of the 15 gymnasts with standard errors of estimate between 0.02 and 0.28 cm. Maturity offset was calculated from measurements taken at each observation for the 13 gymnasts and also added to chronological age at each observation point to provide an estimated age at PHV. Age at PHV derived with the Preece-Baines model was used as the criterion. Differences between the criterion age at PHV and predicted age at PHV were calculated. RESULTS: Maturity offset overestimates age at PHV in gymnasts. Mean predicted ages at PHV deviate linearly from the criterion age at PHV, but the difference is significant only at 9 yr. Correlations between maturity offset predicted ages at PHV and criterion age at PHV range from -0.13 to +0.76. The Bland-Altman plot of criterion and predicted ages at PHV suggest a systematic bias in the predictions. CONCLUSION: Maturity offset appears to have limitations when applied to female gymnasts. Care is warranted in utilizing maturity offset per se and predicted age at PHV based on maturity offset as an indicator of maturity timing in female gymnasts and perhaps other short females.     

How does brain activation differ in children with unilateral cerebral palsy compared to typically developing children, during active and passive movements, and tactile stimulation? An fMRI study

The aim of the functional magnetic resonance imaging (fMRI) study was to investigate brain activation associated with active and passive movements, and tactile stimulation in 17 children with right-sided unilateral cerebral palsy (CP), compared to 19 typically developing children (TD). The active movements consisted of repetitive opening and closing of the hand. For passive movements, an MRI-compatible robot moved the finger up and down. Tactile stimulation was provided by manually stroking the dorsal surface of the hand with a sponge cotton cloth. In both groups, contralateral primary sensorimotor cortex activation (SM1) was seen for all tasks, as well as additional contralateral primary somatosensory cortex (S1) activation for passive movements. Ipsilateral cerebellar activity was observed in TD children during all tasks, but only during active movements in CP children. Of interest was additional ipsilateral SM1 recruitment in CP during active movements as well as ipsilateral S1 activation during passive movements and tactile stimulation. Another interesting new finding was the contralateral cerebellum activation in both groups during different tasks, also in cerebellar areas not primarily linked to the sensorimotor network. Active movements elicited significantly more brain activation in CP compared to TD children. In both groups, active movements displayed significantly more brain activation compared to passive movements and tactile stimulation.     

Derivatives of the Mouse Cathelicidin-Related Antimicrobial Peptide (CRAMP) Inhibit Fungal and Bacterial Biofilm Formation

We identified a 26-amino-acid truncated form of the 34-amino-acid cathelicidin-related antimicrobial peptide (CRAMP) in the islets of Langerhans of the murine pancreas. This peptide, P318, shares 67% identity with the LL-37 human antimicrobial peptide. As LL-37 displays antimicrobial and antibiofilm activity, we tested antifungal and antibiofilm activity of P318 against the fungal pathogen Candida albicans. P318 shows biofilm-specific activity as it inhibits C. albicans biofilm formation at 0.15 μM without affecting planktonic survival at that concentration. Next, we tested the C. albicans biofilm-inhibitory activity of a series of truncated and alanine-substituted derivatives of P318. Based on the biofilm-inhibitory activity of these derivatives and the length of the peptides, we decided to synthesize the shortened alanine-substituted peptide at position 10 (AS10; KLKKIAQKIKNFFQKLVP). AS10 inhibited C. albicans biofilm formation at 0.22 μM and acted synergistically with amphotericin B and caspofungin against mature biofilms. AS10 also inhibited biofilm formation of different bacteria as well as of fungi and bacteria in a mixed biofilm. In addition, AS10 does not affect the viability or functionality of different cell types involved in osseointegration of an implant, pointing to the potential of AS10 for further development as a lead peptide to coat implants.